U.S. patent application number 10/949665 was filed with the patent office on 2006-03-30 for bipolar valve having permanent magnet.
Invention is credited to Gary Everingham, Craig Andrew Weldon.
Application Number | 20060065250 10/949665 |
Document ID | / |
Family ID | 35998644 |
Filed Date | 2006-03-30 |
United States Patent
Application |
20060065250 |
Kind Code |
A1 |
Weldon; Craig Andrew ; et
al. |
March 30, 2006 |
BIPOLAR VALVE HAVING PERMANENT MAGNET
Abstract
A solenoid for use in valves used in evaporative emission
control systems, such as canister purge valves or vent solenoid
valves. The solenoid includes a housing having an inlet port and an
outlet port. The housing further includes a guide element having a
bobbin section. A valve shaft is slidably mounted to the guide
element, wherein the valve shaft includes a permanent magnet and a
valve element. The valve element is movable between a closed
position wherein the inlet port is closed and an open position
wherein the inlet port is opened. A coil is formed on the bobbin
adjacent the magnet. In use, the coil generates directional
magnetic fields oriented to cause the magnet to be repelled to move
the valve element to the open position and oriented to cause a
magnetic attraction with the magnet to move the valve element to
the closed position.
Inventors: |
Weldon; Craig Andrew;
(Chatham, CA) ; Everingham; Gary; (Chatham,
CA) |
Correspondence
Address: |
Elsa Keller;Intellectual Property Department
Siemens Corporation
186 Wood Avenue South
Iselin
NJ
08830
US
|
Family ID: |
35998644 |
Appl. No.: |
10/949665 |
Filed: |
September 24, 2004 |
Current U.S.
Class: |
123/516 ;
123/520; 251/129.09; 251/65 |
Current CPC
Class: |
F16K 31/082 20130101;
F02M 2025/0845 20130101; F02M 25/0836 20130101; F02M 25/0809
20130101; F16K 24/04 20130101 |
Class at
Publication: |
123/516 ;
123/520; 251/065; 251/129.09 |
International
Class: |
F16K 31/02 20060101
F16K031/02; F16K 31/08 20060101 F16K031/08; F02M 37/20 20060101
F02M037/20 |
Claims
1. A solenoid for use in a valve, comprising: a housing having an
inlet port and an outlet port; a guide element located in said
housing, said guide element including a bobbin section; a valve
shaft slidably mounted to said guide element, said valve shaft
having a permanent magnet and a valve element wherein said valve
element is movable between a closed position wherein said inlet
port is closed and an open position wherein said inlet port is
opened; and a coil formed on said bobbin adjacent said magnet,
wherein said coil generates a first magnetic field having a first
polarity that is oriented to move said valve element to said open
position and wherein said coil generates a second magnetic field
having a second polarity that is oriented to move said valve
element to said closed position.
2. The solenoid according to claim 1, wherein an orientation of
magnetic poles generated by said first magnetic field relative to
said second magnetic field is reversed.
3. The solenoid according to claim 1, wherein a voltage of
approximately 12 volts is applied to a first terminal of said
coil.
4. The solenoid according to claim 1, wherein a voltage of
approximately 12 volts is applied to a second terminal of said
coil.
5. The solenoid according to claim 1, wherein a magnetic latch is
formed between said bobbin and said magnet.
6. The solenoid according to claim 1, wherein a portion of said
bobbin is fabricated from a nonmagnetic material.
7. A method for operating a valve, comprising the steps of:
providing a housing having a inlet port and an outlet port;
providing a valve shaft having a permanent magnet and a valve
element, wherein said valve element is movable between a closed
position wherein said inlet port is closed and an open position
wherein said inlet port is opened; generating a first magnetic
field having a polarity that is oriented to cause said magnet to be
repelled to move said magnet and thus said valve element to said
open position; and generating a second magnetic field having a
reverse polarity that is oriented to cause a magnetic attraction
with said magnet to move said magnet and thus said valve element to
said closed position.
8. The method according to claim 7, wherein a voltage of
approximately 12 volts is applied to a first terminal of said coil
to generate said first magnetic field.
9. The method according to claim 7, wherein a voltage of
approximately 12 volts is applied to a second terminal of said coil
to generate said second magnetic field.
10. An evaporative emission control system, wherein said system is
in fluid communication with a fuel tank that generates fuel vapors,
comprising: a vapor collection canister in fluid communication with
said fuel tank for absorbing fuel vapors in said system; a vent
valve in fluid communication with said canister for enabling
venting of said canister to atmosphere; a leak detection monitor
for determining whether there are leaks in said system which are
greater than a predetermined level; a canister purge valve which
further comprises: a housing having an inlet port in fluid
communication with said canister and an outlet port in fluid
communication with an intake manifold of an engine; a guide element
located in said housing, said guide element including a bobbin
section; a valve shaft slidably mounted to said guide element, said
valve shaft having a permanent magnet and a valve element wherein
said valve element is movable between a closed position wherein
said inlet port is closed and an open position wherein said inlet
port is opened; a coil formed on said bobbin adjacent said magnet,
wherein said coil generates a first magnetic field having a
polarity that is oriented to cause said magnet to be repelled to
move said valve element to said open position and wherein said coil
generates a second magnetic field having a polarity that is
oriented to cause a magnetic attraction with said magnet to move
said valve element to said closed position; and an electronic
engine control unit for controlling opening and closing of said
vent valve and said canister purge valve to enable purging of said
canister and performance of an on board diagnostic procedure.
11. The solenoid according to claim 10, wherein an orientation of
magnetic poles generated by said first magnetic field relative to
said second magnetic field is reversed.
12. The solenoid according to claim 10, wherein a voltage of
approximately 12 volts is applied to a first terminal of said
coil.
13. The solenoid according to claim 10, wherein a voltage of
approximately 12 volts is applied to a second terminal of said
coil.
14. The system according to claim 10 further including bearings for
enabling movement of said valve shaft.
15. The system according to claim 10 further including a filter in
fluid communication with said vent valve.
16. The solenoid according to claim 10, wherein a magnetic latch is
formed between said bobbin and said magnet.
17. The solenoid according to claim 10, wherein a portion of said
bobbin is fabricated from a nonmagnetic material.
Description
FIELD OF THE INVENTION
[0001] This invention relates to evaporative emission control
systems for internal combustion engines, and more particularly, to
a valve having a bipolar coil for generating magnetic fields which
interact with a permanent magnet to selectively open and close a
valve element.
BACKGROUND OF THE INVENTION
[0002] Motor vehicles having an internal combustion engine
typically include an evaporative emission control system which
serves to reduce fuel vapor emissions. Such systems include a vapor
collection canister having carbon or other material which serves to
absorb fuel vapors that are generated within a motor vehicle fuel
system. A canister purge valve is located between the canister and
an engine intake manifold. The canister purge valve may be opened
or closed to either place the canister in fluid communication with
the engine intake manifold or to isolate the canister from the
engine intake manifold, respectively. The canister is also
connected to a vent solenoid valve which serves to place the
canister in fluid communication with atmospheric air and to isolate
the canister from atmospheric air.
[0003] Under the appropriate conditions, the canister is purged so
that fuel vapors collected within the canister do not undesirably
escape into the atmosphere. This is done by opening the canister
purge valve and the vent solenoid valve, thus enabling vacuum
generated by the engine to draw in atmospheric air through the
canister and then draw out the fuel vapors from the canister as
part of a process for purging the canister. The fuel vapors are
then used in the normal combustion process. Alternatively, the vent
solenoid valve is closed to isolate the canister from atmospheric
air. This enables the performance of a selected on board diagnostic
procedure for detecting whether there is a fuel vapor leak in the
system that is above a predetermined level.
[0004] Conventional canister purge and vent solenoid valves include
a solenoid and spring arrangement for moving a valve element
between open and closed positions. During operation, the solenoid
is energized so as to move the valve element to a desired position.
The spring serves to return the valve element to its initial
position when power to the solenoid is removed.
[0005] However, the use of such valves increases the amount of
components needed and thus increases manufacturing and other costs.
Therefore, there is a need for valves having a reduced number of
components and which cost less to manufacture and assemble.
SUMMARY OF THE INVENTION
[0006] The invention is directed to a solenoid for use in valves
used in evaporative emission control systems, such as canister
purge valves or vent solenoid valves. The solenoid includes a
housing having an inlet port and an outlet port. The housing
further includes a guide element having a bobbin section. A valve
shaft is slidably mounted to the guide element, wherein the valve
shaft includes a permanent magnet and a valve element. The valve
element is movable between a closed position wherein the inlet port
is closed and an open position wherein the inlet port is opened. A
coil is formed on the bobbin adjacent the magnet. In use, the coil
generates a first directional magnetic field that is oriented to
cause the magnet to be repelled to thus move the valve element to
the open position. The coil also generates a second directional
magnetic field that is oriented to cause a magnetic attraction with
the magnet to move the valve element to the closed position.
[0007] The features of the invention believed to be novel are set
forth with particularity in the appended claims. The invention
itself, however, both as to organization and method of operation,
may be best understood by reference to the following description
taken in conjunction with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a cross sectional view of a bipolar canister purge
valve having a coil which is energized for opening an inlet
port.
[0009] FIG. 2 is a cross sectional view of the bipolar valve having
wherein the coil is energized for closing the inlet port.
[0010] FIG. 3 is an illustrative depiction of the canister purge
valve in an evaporative emission control system.
DETAILED DESCRIPTION OF THE INVENTION
[0011] While this invention is susceptible of embodiment in many
different forms, there is shown in the drawings and will herein be
described in detail specific embodiments, with the understanding
that the present disclosure is to be considered as an example of
the principles of the invention and not intended to limit the
invention to the specific embodiments shown and described. In the
description below, like reference numerals are used to describe the
same, similar or corresponding parts in the several views of FIGS.
1-3.
[0012] The principles of the present invention may be applied to
either canister purge valves or vent solenoid valves. For purposes
of clarity, the invention will be described in relation to a
canister purge valve configuration although it is understood that
the principles of the present invention are also applicable to vent
solenoid valves. Referring to FIG. 1, a cross sectional view of a
bipolar canister purge valve 10 in accordance with the present
invention is shown. The purge valve 10 includes a housing 12 having
a lower wall 14 and an internal wall 16 for forming an internal
passageway 18. Inlet port walls 20 extend from the lower wall 14 to
form an inlet port 22 having a first passageway 24 which is in
fluid communication with a vapor collection canister 26 (FIG. 3). A
valve seat 28 for receiving a valve element 30 is formed at the
intersection of the inlet port walls 20 and the lower wall 14.
Outlet port walls 32 extend from a side wall 34 of the housing 12
to form an outlet port 36 having a second passageway 38 which is in
fluid communication with an engine intake manifold 97 (FIG. 3).
[0013] The housing 12 further includes a guide member 42 having a
bobbin section 44 located between upper 46 and lower 48 flanges
that extend outwardly to form a substantially C-shaped
configuration. The upper flange 46 is fabricated from a
non-magnetic material. Alternatively, an air gap may be formed
between the upper flange 46 and remaining portions of the bobbin
section 44 to isolate the upper flange 46. The upper 46 and lower
48 flanges each include bearings 50 for enabling movement of a
shaft 52 along an axial direction. It is noted that other devices
and configurations for enabling movement may be used such as
bushings. The shaft 52 includes a permanent magnet 54 that is
located between the upper 46 and lower 48 flanges. A lower end 56
of the shaft 52 includes the valve element 30. In FIG. 1, the valve
element 30 is depicted in an open position wherein the valve
element 30 is spaced apart from the valve seat 28 to enable fluid
communication between the first passageway 24, the internal
passageway 18 and the second passageway 38. The valve element 30
may also be moved to a closed position wherein the valve element 30
is in contact with the valve seat 28 to thus close the inlet port
22 as will be described in relation to FIG. 2.
[0014] A wire 58 having first 60 and second 62 ends is wound around
a section of the bobbin 44 to form a coil 65. The first 60 and
second 62 ends are connected to first 76 and second 72 terminals,
respectively. The coil 65 is located adjacent the magnet 54. In one
embodiment, the magnet 54 is oriented such that the south and north
magnetic poles are located adjacent first 82 and second 84
portions, respectively of the coil 65. In operation, the coil 65 is
energized by maintaining the second terminal 72 at 0 volts and the
first terminal 76 at a positive voltage such as approximately +12
volts, for example. The coil 65 is wound such that a magnetic field
is generated having south and north magnetic poles oriented near
top 82 and bottom 84 portions, respectively, of the coil 65. As a
result, the polarity of the magnetic field along the bobbin 44 is
oriented to repel the magnet 54, thus causing the valve element 30
to move upward to the open position as shown in FIG. 1.
[0015] Referring to FIG. 2, the valve element 30 is shown in the
closed position. In order to move the valve element 30 to the
closed position, the voltage applied to the first 76 and second 72
terminals is reversed. In particular, coil 65 is energized by
maintaining the first terminal 76 at 0 volts and the second
terminal 72 at a positive voltage such as approximately +12 volts,
for example. As a result, the orientation of the magnetic poles
along the bobbin 44 is reversed from that which occurs when the
valve element 30 is moved to the first position so as to form a
bipolar coil. Thus, a magnetic field is generated having north and
south magnetic poles oriented near the top 82 and bottom 84
portions, respectively, of the coil 65. As a result, the polarity
of the magnetic field along the bobbin 44 is oriented to
magnetically attract the magnet 54. This causes the valve element
30 to move downward to the closed position as shown in FIG. 2.
[0016] In the second position, the magnet 54 is located so as to
form a magnetic latch between the magnet 54 and the lower flange
48. This serves to maintain the valve element 30 in the closed
position when the coil 65 is not energized, thus reducing the
amount of power required for operating the purge valve 10. In FIG.
2, the magnet 54 is shown in contact with the lower flange 48.
Alternatively, the magnet 54 may be spaced apart and located in
sufficient proximity to the lower flange 48 to form the magnetic
latch.
[0017] In order to move the valve element 30 back to the open
position, the voltage applied to the first 76 and second 72
terminals is again reversed such that a magnetic field is generated
having south and north magnetic poles oriented near top 82 and
bottom 84 portions, respectively, of the coil 65 as previously
described in relation to FIG. 1. The magnetic field is of
sufficient strength to overcome the magnetic latch between the
magnet 54 and the lower flange 48. As such, the polarity of the
coil 65 may be selectively reversed to cause movement of the valve
element 30 between the open and closed positions. In addition,
movement of the valve element 30 between the open and closed
positions is achieved without the use of a spring. It is noted that
other suitable voltages may be used to energize coil 65. Further,
it is noted that the polarity of the magnet 54 and that of the
magnetic field generated by coil 65 may be correspondingly reversed
as desired to enable movement of the valve element 30 between the
open and closed positions. In one embodiment, pulse width
modulation techniques may be used to control movement of the valve
element 30. In another embodiment, the coil 56 may be wound around
the magnet 54 to form a coaxial configuration.
[0018] Referring to FIG. 3, the purge valve 10 in accordance with
the present invention is shown in an emission control system 90.
The system 90 includes a leak detection monitor 92 which is used as
part of a selected on board diagnostic procedure for determining
whether there is an unacceptable fuel vapor leak in the system
90.
[0019] The canister 26 is in fluid communication with a fuel tank
94 and includes carbon or other similar material which serves to
absorb fuel vapors that are generated within the fuel tank 94 and
in the emission control system 90. The canister 26 also includes a
vent solenoid valve 96 which is opened under the appropriate
conditions so as to place the canister 26 in fluid communication
with atmospheric air through a filter 40. Alternatively, the vent
valve 96 is closed to isolate the canister 26 from atmospheric air
so as to enable performance of an on board diagnostic procedure. As
previously described, the principles of the present invention
regarding the use of a bipolar coil may be applied to either
canister purge valves or vent solenoid valves. In addition, for
vent valve applications, the coil 65 may be energized to a higher
level when the valve element 30 is in the closed position than in
purge valve applications so as to achieve an improved seal between
the valve element 30 and the valve seat 28.
[0020] The purge valve 10 is located between the canister 26 and
the engine intake manifold 97 of an internal combustion engine 98.
The purge valve 10 may be opened as previously described in
relation to FIG. 1 to place the canister 26 in fluid communication
with the intake manifold 97. Alternatively, the purge valve 10 may
be closed as previously described in relation to FIG. 2 to isolate
the canister 26 and the fuel tank 94 from the intake manifold 97.
The opening and closing of both the purge valve 10 and the vent
valve 96 is controlled by an engine electronic control unit (ECU)
99.
[0021] Under the appropriate conditions, the canister 26 is purged
so that fuel vapors collected within the canister 26 do not
undesirably escape into the atmosphere. This is done by opening
both the purge valve 10 and the vent valve 96, thus enabling vacuum
which is present at the intake manifold 97 to draw in atmospheric
air through the canister 26 and then draw out the fuel vapors from
the canister 26. The purged fuel vapors are then used in the normal
combustion process. The ECU 99 determines when purging is to occur
based on received signals indicative of various engine parameters.
Further, the ECU 99 may be programmed to allow purging of the
canister 26 at differential rates depending upon the prevailing
engine operating conditions. As such, greater amounts of purging
may be permitted at certain times while at other times lesser
amounts may be allowed.
[0022] While the invention has been described in conjunction with
specific embodiments, it is evident that many alternatives,
modifications, permutations and variations will become apparent to
those skilled in the art in light of the foregoing description.
Accordingly, it is intended that the present invention embrace all
such alternatives, modifications and variations as fall within the
scope of the appended claims.
* * * * *